A review of practical aspects to implementing geomorphic landform design with Liddell Open Cut as a case study

Authors: Dressler, S; Waygood, C Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2615_58

Cite As:
Dressler, S & Waygood, C 2026, 'A review of practical aspects to implementing geomorphic landform design with Liddell Open Cut as a case study', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-11, https://doi.org/10.36487/ACG_repo/2615_58



Abstract:
Liddell Open Cut mined its last coal in 2023 after 100years of operation. Currently in the final stages of mine closure and rehabilitation, the site is interesting from a landform perspective having a mixture of traditional and geomorphic landforms and a wide range of average slopes, from very flat to as steep as 22 degrees. Geomorphic design has been implemented at Liddell Open Cut since 2016 but used on open cut coal mines in New South Wales (NSW) Australia since 2012. We now have well over 130 years of cumulative experience considering all of the sites (more than 20 mines) through a range of climatic conditions from some of the wettest seasons on record, and including extreme drought. While the rainfall averages between 600 to 800 mm in most of these areas, it is highly variable. However, the use of the methodology outside of NSW has been relatively limited. This is partly due to NSW being extremely well suited to a geomorphic approach, with historically outer slopes of 15 per cent being used. The mines are located relatively close to towns, with a strong focus on limiting visual impacts and ensuring integration ecologically and hydrologically with the surrounding areas. There are also site-specific limitations to applying a geomorphic approach, for example, in arid areas, water tends to be contained on the landform and drainage may not always be required or desirable, or there may be additional cost such as having to implement flatter outer gradients. However, we also believe that there are still many misunderstandings around geomorphic landforms, when and where they may be applicable, and how designs could potentially be adjusted to suit different site constraints such as cyclonic rainfall for example, or highly erodible soils. The intent of the paper is not to promote one approach above all others, but rather to provide an overview of some of these issues from the experience at Liddell Open Cut, primarily to highlight relevant issues and limitations to both geomorphic and traditional landforms and to identify opportunities that may exist to apply different design concepts for different conditions and limitations.

Keywords: geomorphic, practical, slope, soils, erosion

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